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Changing database in Phreeplot
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Topic: Changing database in Phreeplot (Read 631 times)
jt2020
Frequent Contributor
Posts: 21
Changing database in Phreeplot
«
on:
April 29, 2021, 12:49:23 PM »
Hello there,
I am trying to produce phase diagrams in Phreeplot and need to change database from wateq4f.dat to minteq.dat. After that, ill have to try producing phase diagrams at different temperatures and pressures (but one step at a time).
I have added minteq.dat to the input file but when running it, it says that the main species, Fe, could not be found. Odd, as it is in the Minteq database which is very similar to wateq4f.dat. I have copied my input below.
SPECIATION
JobTitle "Test"
database MINTEQ.DAT
calculationType ht1 # hunt & track method - could also use 'grid' approach
calculationMethod 1
mainSpecies Fe
resolution 200
xmin 2.0 # this determines the scope of the x-axis variable
xmax 12.0 # ibid
ymin -85.0 # this determines the scope of the y-axis variable
ymax 0.0 # ibid
pdf T # file conversions using Ghostscript
png T
jpg T
eps T
PLOT
plotTitle "Fe-O<sub>2</sub>-H<sub>2</sub>O"
xtitle "pH"
ytitle "Eh (V)"
yscale Eh # this makes the y-axis 'Eh' rather than log f O2(g)
text auto 10.5 1.1 "<mainspecies>" 5 blue 0 1:\
auto 2.5 -0.8 "0.1 mol/kgw NaCl25<sup>o</sup>C" 2 black 0 0
# nudge measures shift in labels in terms of the units of distance in force - here assumes the default, i.e. mm
# nudge plotnumber labelnumber label diff/abs x y [angle pos]
nudge 1 auto "O2(g) > 0.21 atm" diff 0 0 : 1 auto "H2(g) > 1 atm" diff 0 -1.5
CHEMISTRY
include 'ht1.inc' # this pulls in the special hunt and track code from the system directory
SOLUTION 1
pH 1.8 # starting with a low pH ensures that the entire pH range from 2-12
units mol/kgw # can be reached by titration with NaOH
Fe(2) 1e-6
S(-2) 1e-4
HCO3- 1e-2
Na 1e-1
Cl 1e-1
SAVE solution 1
END
# second simulation - by default, loops on the last simulation only
USE solution 1
EQUILIBRIUM_PHASES 1
Fix_H+ -<x_axis> NaOH 10
-force_equality true
O2(g) <y_axis> 0.1
Fe(OH)3(a) 0 0
Magnetite 0 0
Hematite 0 0
Greigite 0 0
Siderite 0 0
END
Hope you can help,
Thanks
Jack
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dlparkhurst
Top Contributor
Posts: 2736
Re: Changing database in Phreeplot
«
Reply #1 on:
April 29, 2021, 03:42:37 PM »
The problem is that Fe(OH)3(a) is not defined in minteq.dat. I found the problem by running a straight PHREEQC calculation.
Add the following before the SOLUTION 1 definition:
Code:
[Select]
PHASES
Fe(OH)3(a)
Fe(OH)3 + 3 H+ = Fe+3 + 3 H2O
-log_k
4.891
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jt2020
Frequent Contributor
Posts: 21
Re: Changing database in Phreeplot
«
Reply #2 on:
April 30, 2021, 11:46:18 AM »
Ah I see,
Thank you! I'll give it a go
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Changing database in Phreeplot